The present invention pertains to the field of image processing. More particularly, the present invention relates to the display of facsimile documents on computer display devices.
As a result of technological advances such as the fax-modem, it has become common to send and receive facsimile (xe2x80x9cfaxxe2x80x9d) documents with personal computers rather than with dedicated fax machines. The use of computers to communicate and display faxed documents has many advantages over the use of dedicated fax machines, such as facilitating the editing of faxed documents. However, the quality of text tends to degrade when a faxed document is displayed on a computer monitor. This degradation occurs primarily because the spatial resolution of most computer monitors is much lower than that of most printed faxes. Current printed fax technology can provide a resolution of 1728 pixels by 2376 pixels for A4 size paper. In contrast, currently available high-quality computer monitors generally cannot provide a resolution greater than about 1280 by 1000 pixels, and some less expensive computer monitors cannot provide a resolution greater than 640 by 480 pixels. A similar loss in quality also tends to occur when a scanned document is displayed on a computer monitor, for essentially the same reason. One common result of some resolution reduction methods is that text appears to be out of focus, or xe2x80x9cwashed outxe2x80x9d.
A good method of displaying text images at low resolution is essential to any software package designed to display scanned or faxed images on a monitor. One way to produce more readable documents on screen is to utilize optical character recognition (OCR) products to reproduce text on screen. For many reasons, however, it may be desirable to avoid performing OCR. It is therefore desirable to perform resolution reduction on scanned or faxed documents for display on a computer monitor in a manner that reduces or eliminates degradation in image quality, particularly with respect to text images.
For purposes of editing a scanned or faxed document, it may be desirable to view the entire document on the monitor at one time. A person who is editing the layout of a page for publication, for example, may need to view the entire page at once in order to work efficiently. One problem associated with existing display software, however, is that due to the change in resolution, the entire document generally cannot be displayed on the monitor at once while still maintaining adequate readability. While portions of a displayed page can be magnified to provide greater readability, the remaining portions of the page are generally hidden from view. Although the page can be reduced in size in order to fit the page to the screen, the text often becomes too small to read. Consequently, a person editing the document may be required to scroll up and down the displayed document repeatedly, which can be annoying and time consuming.
Hence, it would be desirable to have a technique for improving the quality of display on a computer monitor of scanned or faxed documents. In particular, it would be desirable to have a technique for increasing the readability of text in scanned or faxed documents when displayed on a monitor, and for facilitating the editing of such documents.
One aspect of the present invention is a method of generating an output image from a source image, such that the output image has a lower resolution than that of the source image. In the method, a first process is performed on the source image to generate a first image, which has a resolution lower than that of the source image. A second process is performed on the source image in parallel with the first process to generate a second image, which also has a resolution lower than that of the source image. The output image is then generated as a function of the first image and the second image.
In another aspect of the present invention, a first image is provided at a first resolution and a second image is provided at a second resolution, which is different from the first resolution. A pattern is identified in the source image, and a value is assigned to a subset of the output image based on a relationship between the first image and the second image with respect to the pattern.
In yet another aspect of the present invention, blank space is removed from an input page that includes a plurality of images, by representing the images as a plurality of objects, and then locating each of the objects on an output page, such that the spacing between the objects in the output page is smaller than the spacing of the objects in the input page.
Other features of the present invention will be apparent from the accompanying drawings and from the detailed description which follows.